The objective of the proposed study is to investigate the following hypothesis: The serum proteins induced by estrogen and by organochlorine xenobiotic exposure(a) are identical, (b) demonstrate preferential binding to organochlorine xenobiotics and (c) provide a transport system of organochlorine xenobiotics into developing eggs. This hypothesis is based on the facts that: estrogen induces the hepatic synthesis of the serum lipoprotein vitellogenin which is incorporated into the yolk of developing eggs in non-mammalian vertebrates; some organochlorine xenobiotics are extrogenic; organochlorine xenobiotics bind to serum proteins; and organochlorine xenobiotics accumulate in eggs. In addition, unpublished data from our laboratory indicated a serum protein presumably induced by environmental exposures to pollutants which is electrophoretically analogous to a presumed vitellogenic protein in fish. The experiments are designed to characterize the serum proteins induced by estrogen and by organochlorine xenobiotics to investigate their hypothesized identity. Compounds selected for study are the estrogenic insecticides o, p'-DDT, methoxychlor and kepone and the non-estrogenic insecticides or derivatives, mirex, o,p'-DDE and dieldrin. The experimental model will be adult femal channel catfish (Ictalurus punctatus). Electrophoretic mobility, molecular weight (SDS gel electrophoresis and gel filtration), relative density, and contents of protein, lipid, calcium and phosphorus will be investigated in the purified proteins. The affinity of the estrogen induced protein for DDT, mirex, kepone and dieldrin will be compared to the affinity of other serum proteins. In addition, egg proteins will be isolated and characteristics of these proteins will be studied and compared to paralled parameters of the induced serum protein. Organochlorine xenobiotic binding affinity to the egg proteins as well as in vivo accumulation of these compounds in eggs will be investigated to gather information regarding the hypothesized transport mechanism of organochlorine xenobiotics into developing eggs.